The present invention is generally directed to toner and developer compositions, and more specifically, the present invention is directed to blending, or mixing processes for the preparation of toner compositions. In embodiments, there are provided in accordance with the present invention processes to achieve effective toner blending or comixing compatibility, that is for example the overlapping of charge spectra and rapid blend admixing of the constituents in a blend of dry toner compositions comprised of resin particles, pigment particles, and optional charge additives dispersed therein, such as quaternary ammonium hydrogen bisulfates, including distearyl methyl hydrogen ammonium bisulfate, and the like by, for example, mixing a toner with a high concentration of additives, or a masterbatch with a toner with no additives; or mixing a first toner with a second toner and wherein the first toner contains additives. Accordingly, in embodiments of the present invention a first color toner with surface additives present in an amount of from about 0.4 to about 0.8 is diluted with a second color toner with no surface additives, and wherein the toner resulting contains surface additives in an amount that is less than that present in the first toner, for example the resulting toner contains two surface additives, each present, for example, in an amount of from about 0.2 to about 0.4 weight percent. More specifically, in embodiments the present invention is directed to the blending of two Xerox Corporation 4850 dry toners with additives in a two step process wherein excessive additives are blended with one toner and the resulting masterbatch is diluted with a second toner that contains no additives. Additives in embodiments refers to surface additives, such as silicas like the AEROSILS.RTM., metal salts of fatty acids, such as zinc stearates, metals, metal oxides, mixtures thereof, and the like. Thus, in embodiments with the present invention there can be obtained a palette, that is for example preselected colored toners, or an extended set of colors by admixing certain toner compositions. One object of mixing or blending is to enable a minimum starting set of toners, such as red, green, blue, cyan, magenta and yellow, to generate many other colors by the method of comixing these toners, pairwise in embodiments, to provide toners with preselected colors, thus each new comixture, with a relative ratio of the constituent pair, can become a new toner to be added to a carrier to form a developer particularly useful in trilevel or color xerography. The aforementioned toner compositions usually contain pigment particles comprised of, for example, carbon black, magnetites, or mixtures thereof, cyan, magenta, yellow, blue, green, red, or brown components, or mixtures thereof thereby providing for the development and generation of black and/or colored images. The toner compositions of the present invention in embodiments thereof possess excellent admix characteristics, and maintain their triboelectric charging characteristics for an extended number of imaging cycles, exceeding for example 50,000 in a number of embodiments. The toner and developer compositions of the present invention can be selected for electrophotographic, especially xerographic, imaging and printing processes, including trilevel and full color processes.
Toner and developer compositions are generally known, reference for example U.S. Pat. No. 4,338,390, the disclosure of which is totally incorporated herein by reference, wherein there are disclosed developer compositions containing as charge enhancing additives organic sulfate and sulfonates, which additives can impart a positive charge to the toner composition. Further, there are disclosed in U.S. Pat. No. 4,298,672, the disclosure of which is totally incorporated herein by reference, positively charged toner compositions with resin particles and pigment particles, and as charge enhancing additives alkyl pyridinium compounds. Additionally, other patents disclosing toner compositions and processes thereof include U.S. Pat. Nos. 3,944,493; 4,007,293; 4,079,014; 4,394,430; 4,937,157 and 4,560,635, which illustrates a toner with a distearyl dimethyl ammonium methyl sulfate charge additive.
Moreover, toner compositions with negative charge enhancing additives are known, reference for example U.S. Pat. Nos. 4,845,003; 4,411,974 and 4,206,064, the disclosures of which are totally incorporated herein by reference. The '974 patent discloses negatively charged toner compositions comprised of resin particles, pigment particles, and as a charge enhancing additive ortho-halo phenyl carboxylic acids. Similarly, there are disclosed in the '064 patent toner compositions with chromium, cobalt, and nickel complexes of salicylic acid as negative charge enhancing additives.
There is illustrated in U.S. Pat. No. 4,404,271 a process for developing electrostatic images with a toner, which contains a metal complex represented by the formula in column 2, for example, and wherein ME can be chromium, cobalt or iron. Additionally, other patents disclosing various metal containing azo components wherein the metal can be chromium or cobalt include 2,891,939; 2,871,233; 2,891,938; 2,933,489; 4,053,462 and 4,314,937. Also, in U.S. Pat. No. 4,433,040, the disclosure of which is totally incorporated herein by reference, there are illustrated toner compositions with chromium and cobalt complexes of azo dyes as negative charge enhancing additives.
The disclosures of each of the U.S. patents mentioned herein, especially as they relate to toners, are totally incorporated herein by reference.
In U.S. Pat. No. 5,370,962, the disclosure of which is totally incorporated herein by reference, there is illustrated a process for the preparation of colored toners which comprises providing a first toner comprised of resin, pigment particles, internal charge additive, and optional surface additives; adding thereto a second toner comprised of resin, pigment particles, internal charge additive, and optional surface additives; and wherein said toners contain blend compatibility components.